User`s guide

Functions and Measurements 3
N9320A Spectrum Analyzer 51
Third-Order Intermodulation Distortion
Two- tone, third- order intermodulation distortion is a
common specification in communication systems. When two
signals are present in a non- linear system, they may interact
and create third- order intermodulation distortion (TOI)
products that are located close to the original signals.
System components such as amplifiers and mixers contribute
to the generation of these distortion products.
For an example of the quick setup of TOI measurement,
refer to “Intermod (TOI)” on page 130.
This example will test a device for third- order
intermodulation through the use of markers. Two sources
are used, one set to 300 MHz and the other to 301 MHz.
1 Connect the equipment as shown in figure below. This
combination of signal generators, low pass filters, and
directional coupler (used as a combiner) results in a
two- tone source with very low intermodulation distortion.
Although the distortion from this setup may be better than
the specified performance of the analyzer, it is useful for
determining the TOI performance of the source/analyzer
combination. After the performance of the source/analyzer
combination has been verified, the device- under- test (DUT)
(for example, an amplifier) would be inserted between the
directional coupler output and the analyzer input.
Fre q ue n cy
Enter
7
MOD
On/Off
RF
4
1
0
2
9
6
3
On/Off
Amplitude FM
Utility
LF Out
Preset
Local
AM I/ Q
File
TriggerPulseM
·
Sweep
8
FUNCTIONS
LF OUT RF OU T 50
Remote
Standby
On
N9310A RF Signal Generator 9 kHz - 3.0 GHz
5
REVERSE PWR
4W MAX 30VDC
Fre q ue n cy
Enter
7
MOD
On/Off
RF
4
1
0
2
9
6
3
On/Off
Amplitude FM
Utility
LF Out
Preset
Local
AM I/ Q
File
TriggerPulseM
·
Sweep
8
FUNCTIONS
LF OUT RF OU T 50
Remote
Standby
On
N9310A RF Signal Generator 9 kHz - 3.0 GHz
5
REVERSE PWR
4W MAX 30VDC
Remo t e
Standby
On
TG SOURCE CAL OUT
50MHz 10dBm
7
·
4
1
0
2
5
89
6
3
Back
Enter
Marker
Peak
Search
Marker
Auto
Tune
Det/
Display
File/
Print
BW/
Avg
View/
Trace
Meas
MODE
Sweep/
Trig
Local
Save
N9320A SPECTRUM AN ALYZER 9 kHz - 3.0 GHz
PROBE POWER
RF IN 50
50VDC MAX
30dBm 1W MAX
CAT Ⅱ
Signal Generator
Signal Generator
Spectrum Analyzer
Directional Coupler
RF OUT
RF IN
300 MHz LOW
PASS FILTER
300 MHz LOW
PASS FILTER